import {WebexPlugin} from '@webex/webex-core';

import {FileDownloadOptions, IEncryption} from './types';
import {CYPHER} from './constants';
import {WebexSDK} from '../types';

/**
 * @description Encryption APIs for KMS
 * @class
 */
class Cypher extends WebexPlugin implements IEncryption {
  readonly namespace = CYPHER;
  private readonly $webex: WebexSDK;
  registered = false;

  /**
   * Constructs an instance of the class.
   *
   * @param {...any[]} args - The arguments to pass to the superclass constructor.
   *
   * @remarks
   * This constructor calls the superclass constructor with the provided arguments.
   * It also assigns the `webex` property to the `$webex` property, ignoring TypeScript errors.
   */
  constructor(...args: any[]) {
    super(...args);
    this.$webex = (this as WebexPlugin).webex as WebexSDK;
  }

  /**
   * Registers the device to WDM. This is required for metrics and other services.
   * @returns {Promise<void>}
   */
  async register() {
    if (this.registered) {
      this.$webex.logger.info('Cypher: webex.internal.device.register already done');

      return Promise.resolve();
    }

    return this.$webex.internal.device
      .register()
      .then(() => {
        this.$webex.logger.info('Cypher: webex.internal.device.register successful');
        this.registered = true;
      })
      .catch((error) => {
        this.$webex.logger.error(`Error occurred during device.register() ${error}`);

        throw error;
      });
  }

  /**
   * Deregisters the device.
   * @returns {Promise<void>}
   */
  async deregister() {
    if (!this.registered) {
      this.$webex.logger.info('Cypher: webex.internal.device.deregister already done');

      return Promise.resolve();
    }

    return this.$webex.internal.device
      .unregister()
      .then(() => {
        this.$webex.logger.info('Cypher: webex.internal.device.deregister successful');
        this.registered = false;
      })
      .catch((error) => {
        this.$webex.logger.error(`Error occurred during device.deregister() ${error}`);

        throw error;
      });
  }

  /**
   * Downloads and decrypts a file from the given URI.
   *
   * @param {string} fileUri - The URI of the file to be decrypted.
   * @param {FileDownloadOptions} options - The options for file download.
   * @returns {Promise<ArrayBuffer>} A promise that resolves to the decrypted ArrayBuffer.
   * @throws {Error} If the file download or decryption fails.
   *
   * @example
   * ```typescript
   * const attachmentURL = 'https:/myfileurl.xyz/zzz/fileid?keyUri=somekeyuri&JWE=somejwe';
   * const options: FileDownloadOptions = {
   *   useFileService: false,
   *   jwe: somejwe, // Provide the JWE here if not already present in the attachmentURL
   *   keyUri: someKeyUri, // Provide the keyURI here if not already present in the attachmentURL
   * };
   * const decryptedBuf = await webex.cypher.downloadAndDecryptFile(attachmentURL, options);
   * const file = new File([decryptedBuf], "myFileName.jpeg", {type: 'image/jpeg'});
   * ```
   */
  public async downloadAndDecryptFile(
    fileUri: string,
    {useFileService = false, ...options}: FileDownloadOptions = {}
  ): Promise<ArrayBuffer> {
    // Sample fileUri: https://someserver.com/3cc29537-7f39-4cce-b204-a529960997fcab9375d8-4fd4-4788-bb12-18426674e95b.jpg?keyUri=kms://kms.wbx2.com/keys/79be16-a4dd-4195-93ef-a72604509aca&JWE=eyJlbmMiOiJBMjU2R0NNIiwiYWxnIjoiZGlyIn0..EHYI5SmnFisaOJgv.6Ie3Zui7LFtAr4eWMSnxXAzfi8Cgixcy2b9jy9cImDWvBjjvJQfwik7qvZewCaq-u8lhtTbjEzsJLeVtOKhW_9RoZt3U0RQ-cKaSh2RaK3N_mvuH7_BsoXCMf5zxaqP1HD-3jXUtVSnqFYvEGdGRWxTCWK-PK9BoIUjX6v5t22CUNYbBQBuHizLWvrGAM0UkSvFNRX5n07Xd3WVJ7OnIhYi0JvOb50lbZIrBn27AQL-_CIKoOQxQLkW9zmVACsVpHxLZx9wIo9XYsBYADRTZaw_l_uTiosAd2P1QAGHgLr_Q_qf1wGUn3eGhmptpPx-YCSJikvs2DttwWOg_-vg4jI3EiIXlc0gGsDnleeNRguCLtrks0PMz5hOp5_w9Z5EW05Cx2UAztnp1hE9_nCvPP9wTzdHsG3flkK82HMbPpeVStWvWmAlzp24vTw2KzYrCemdS2AkrShWsNt6_G7_G8nB4RhUnZ11MKaduE5jYpCXNcTx84RBYwA.vqYHCx8uIn-IMQAsPvrw
    // KeyUri: An attachment level unique ID generated by Webex KMS post encryption of an attachment. In order to
    // decrypt an attachment, KeyUri is a required parameter.
    // JWE: JWE can be decrypted using KMS key to obtain the SCR key.
    // Decrypting an attachment requires the SCR key parameter.
    // We need to download the encrypted file from the given URI and then decrypt it using the SCR key.
    // The decrypted file is then returned.

    // step 1: parse the fileUri to get the keyUri and JWE
    // step 2: if keyUri and JWE are not present in the fileUri, use the options
    // step 3: use the keyUri to decrypt the JWE to get the SCR
    // step 4: download the file from the fileUri and decrypt it using the SCR

    let keyUri: string | undefined;
    let JWE: string | undefined;
    try {
      const url = new URL(fileUri);
      keyUri = url.searchParams.get('keyUri') ?? undefined;
      JWE = url.searchParams.get('JWE') ?? undefined;
    } catch (error) {
      this.$webex.logger.error(`Cypher: Invalid fileUri: ${(error as Error).message}`);
      throw new Error(
        `Failed to decrypt the JWE: ${(error as Error).message}\nStack: ${(error as Error).stack}`
      );
    }

    // Check if the keyUri and JWE are present, else take it from options
    if (!keyUri || !JWE) {
      keyUri = options.keyUri;
      JWE = options.jwe;
    }

    // Check if the keyUri and JWE are present, else throw an error
    if (!keyUri || !JWE) {
      throw new Error(
        'KeyUri and JWE are required to decrypt the file. Either provide them in the fileUri or in the options.'
      );
    }

    try {
      // Decrypt the JWE to get the SCR
      const scr = await this.$webex.internal.encryption.decryptScr(keyUri, JWE);

      // Start the download and decryption process, returning a promise
      return this.$webex.internal.encryption.download(fileUri, scr, {useFileService});
    } catch (error) {
      const enhancedError = new Error(
        `Failed to decrypt or download the file: ${(error as Error).message}\nStack: ${
          (error as Error).stack
        }`
      );
      enhancedError.cause = error;
      throw enhancedError;
    }
  }
}

export default Cypher;